Replacing timing chain tensioner...need help !!!

My 1995 318i M42 engine is getting the timing chain rattle noise on cold starts and idling, and I have a M44 new-design Febi chain tensioner ordered, and on it's way. I have reviewed my Bentley manual, and the replacement seems fairly straight forward, but I'm a little confused about a couple of things:

1. When compressing the tensioner twice in a vise, oil will seep out of the weep hole. I am assuming that the loss of the oil keeps the tensioner in the compressed state until installation. After installation, how does oil get back into the tensioner so it expands against the chain rail guide? In other words, if I start and run the engine with no tension against the chain, won't that possibly cause the timing chain to jump a sprocket, and ruin the engine??

2. In the Bentley manual, it says that the old design M42 tensioner, is spring-loaded, and when compressed in a vise, a snap ring holds the tensioner in a compressed state. After installation, to uncompress the tensioner, you are suppose to push the chain rail guide against the tensioner. How can you do this, without previously removing the timing chain cover? Bentley is ambiguous in this final step....it implies that this is required for both the M42 and M44 tensioners.

3. I've even seen a BMW shop manual page from a CD, that says something to the effect..." after installation, to release compression of tensioner, turn counter engine-wise "....what the hell is that suppose to mean?

4. Should I drain the engine oil before doing the replacement? Or, is there little engine oil loss?

5.Any other advice, or suggestions would be greatly appreciated.

Thanks